Hook gate for flat bed sewing machines

ABSTRACT

A hook gate for flat bed sewing machines characterized in that the hook is inclined relative to a horizontal line and is placed into a recess formed in the upper portion of the sewing machine bed, along with a freely rotatable latch bracket. The recess is covered by a sliding plate which engages, during its closing and opening displacements, suitable surfaces of the latch bracket to cause the latch bracket to rotate towards and away from the hook gate, respectively.

United States Patent Bianchi HOOK GATE FOR FLAT BED SEWING MACHINES Nereo Bianchi, Pavia, Italy Assignee: Necchi, S.p.A., Pavia, Italy.

Filed: Nov. 7, 1973 Appl. No: 413,572

Related U.S. Application Data Continuation of Ser. No. 268,795. July 3, 1972, abandoned.

Inventor:

Foreign Application Priority Data July 20, 1971 Italy 42956/71,

U.S. Cl. 112/180; 112/181; 112/260 Int. Cl D05b 57/26 I Field of Search 112/157 R, 180, 181, 205, 112/215, 219, 228, 230

References Cited UNITED STATES PATENTS Bell et a1 112/181 51 May 13,1975

1,786,944 12/1930 Hemleb ll2/l8l 2,724,354 11/1955 Matuzas... 112/210 3,072,084 1/1963 Vigorelli 112/180 FOREIGN PATENTS OR APPLICATIONS 171,925 7/1952 Austria 112/181 Primary ExaminerWerner I-I. Schroeder Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [57] ABSTRACT A hook gate for flat bed sewing machines characterized in that the hook is inclined relative to a horizontal line and is placed into a recess formed in the upper portion of the sewing machine bed, along with a freely rotatable latch bracket. The recess is covered by a sliding plate which engages, during its closing and opening displacements, suitable surfaces of the latch bracket to cause the latch bracket to rotate towards and away from the hook gate, respectively.

3 Claims, 4 Drawing Figures PATENTEI] MAY 1 31975 SHEET 10F 2 FIG.

PATENTED MAY 1 3'97?! SHEET 2 OF 2 3,882,805

HOOK GATE FOR FLAT BED SEWING MACHINES This application is a continuation of application Ser. No. 268,795 filed July 3, I972, now abandoned.

The present invention refers to a hook gate for flat bed sewing machines and its main purpose is to create such an arrangement and a configuration of the hook and of the latch bracket that the operations of closing and opening of the latch and the operations to be performed by the operator on the bobbin case carrying the bobbin can take place simply without particular care and skill from the same operator.

In order to achieve the purpose, the technical problem to be solved was to provide a latch bracket displaceable by means of a simple operation from a rest position, in which the bobbin case is free and available for inspection, to a work position, in which the latch urges the bobbin case against the hook.

The resolution of this technical problem was particularly important in the field of flat bed household sewing machines because similar solutions of the known art do not have the same constructive and functional simplicity required of a product intended for generally unskilled operators and whose manufacturing cost must be kept low.

The resolution of the technical problem mentioned above is characterized in that the hook is inclined relative to a horizontal line and is placed into a recess formed in the upper portion of the sewing machine bed, the latch mounting also being placed into the recess, free to oscillate; this recess is covered upwardly by a sliding plate interferring, during its closing and opening displacements, with suitable surfaces drawn up onto said latch mounting to make oscillations toward the hook and away from it respectively.

Further features and advantages of the invention will be apparent from the description and the attached drawings, in which:

FIG. 1 is a plane view of the hook latch group with latch opened,

FIG. 2 is a section view of the group shown in FIG. 1 along line 2-2;

FIG. 3 is a section view similar to the one of FIG. 2 with latch closed; and

FIG. 4 is a side view of the group shown in FIG. 3.

FIG. 3 shows a recess 10 formed in the bed 11 of a sewing machine (not otherwise shown), on which a hook gate body 12 lies together with its latch bracket 13. The recess 10 is closed on the upper portion by needle plate 14 fixed to bed 11 by means of screws 15 and 16 (FIG. I) and by a metallic plate 17 slidable on suitable guides provided on the bed 11, in the A and B directions of the arrow in order to allow inspection of the hook gate, to change the lower thread bobbin, and to allow performing other necessary operations on the machine which will be described hereinafter.

Hook gate 12 has its own axis inclined relative to a horizontal line at an angle of 45 and has a shaft 18 passing through hole 19 formed in wall 20 of recess 10. Rotary hook 21 supports bobbin case 22 laying on the usual race, not shown in the drawings, formed inside rotary hook 21 and is kept in position by a finger 23 projecting downwardly from needle plate 14 and engaging a groove, not shown, on bobbin case 22. Lower thread bobbin 24 is placed into bobbin case 22.

Latch 25 resting on bobbin 24 is mounted on latch bracket 13 by means of screw 27 which is fastened on the latch pin 28 of the same latch.

Latch bracket 13 has an upper portion onto which latch 25 is fixed, and a lower portion having a circular bore forming the seat for pin 29 (FIGS. 1 and 4) fixed to the bed casting. The latch bracket is thus free to rotate around pin 29 and, by the action of spring 30, is forced to assume two extreme well determined positions. In fact spring 30 is fixed at one end to a pin 31 fixed to bed 11 and at the other one to projection 32 of the lower portion of latch bracket 13. Fixing pin 31, the point of projection 32 to which spring 30 is fixed and rotation pin 29 have such relative positions that the bias line of the force of spring 30 is directed upwardly or downwardly to the latch bracket'rotational center for all the angular positions thereof except the particular position in which these three members are aligned. In correspondence with its lower end, latch bracket 13 has an extension 33 in which a hole is formed, a pin 34 being slideable therein in an adjustable manner. As shown in FIG. 3, the end pin 34 lies upon surface 35 provided in the bed casting when bracket 13 is caused to rotate toward hook 12. By adjusting the stroke of pin 34 in its threaded hole, the most suitable position and the contact degree between the two facing position and the contact degree between the two facing surfaces of latch 25 and bobbin case 22 can be determined. In this selected position pin 34 is then fixed by means of nut 36.

It is known that latch 25 is mounted on a mounting with a little elastic springing so that, by the adjustment mentioned above, it is possible to cause latch 25 to lie upon bobbin case 22 with a determined pressure, in such a way that the thread loop can pass softly between the facing surfaces of latch 25 and bobbin case 22 and, at the same time, it is possible to avoid any movement or vibration of bobbin case 22 lying on the hook race. In FIG. 2 latch bracket 13 is shown in its rest position to which latch 25 must be brought when hook inspection is desired. In this position, latch bracket 13 lies on surface 39 of recess 10 formed in bed 11, with member 38 fixable to bracket 13 by means of screw 38. According to the features of the invention, hook opening and closing take place through the sliding of metallic plate 17 along the directions of arrows A and B.

For this purpose metallic plate 17 carries, fixed on its lower portion by means of screws 40, a plate 41 having two extreme vertical walls 42 and 43. When plate 17 slides in the direction of arrow A, the first vertical wall, with reference to FIG. 2, makes contact with inclined surface 44 formed in the upper portion of latch mounting 13 which is therefore urged to rotate and to assume the sewing position of FIG. 3 When the metallic plate 17 is caused to slide in the direction of arrow B, in order to allow hook inspection, front vertical wall 42 contacts point 45 of member 37 urging the latch mounting to rotate clockwise and to assume the rest position of FIG. 2. Vertical wall 43 is used to limit the stroke of plate 17 during its displacement in the direction of arrow B. For this purpose ledge 46 is provided on bed 11. A slit 47 (FIG. 1) is formed inside recess 10 in which a lever 48 slides; lever 48 is used to lower the feed dog when it is desired to use the machine for a darning operation. For this purpose it is necessary to displace lever 48 from its position of FIG. 1, indicated with the normal switch symbol 49, to the position indicated with the darning symbol 50. Thus the lever driving'the feed dog lowering can be hidden in the bed of the sewing machine.

What is claimed is:

l. A hook gate apparatus for flat bed sewing machines comprising:

a large recess formed in a sewing machine bed;

a hook gate body disposed in said recess at an inclined angle to the flat surface of said bed;

a latch bracket pivotally mounted in said recess for engagement with said hook gate body;

a sliding plate slideable on said bed over said recess and capable of covering and uncovering said recess;

contact means fixed to said sliding plate for coming temporarily into contact with said latch bracket during the sliding movements of said sliding plate from a closed to an open position and from an open to a closed position to initiate disengagement and engagement, respectively, of said latch bracket with said hook gate body, said contact means comprising a first member disposed on said sliding plate and extending vertically downwardly into said recess for temporarily contacting said latch bracket and a second member disposed on said sliding plate and extending vertically downwardly into said recess for contacting a stop member on said bed to limit the opening stroke of said sliding plate;

mounting means for said latch bracket at the bottom of said recess permitting said latch bracket to be swung within said recess from a closed to an open position; and

spring means attached to said bed and latch bracket to bias said latch bracket in a closed and open position.

2. The hook gate apparatus of claim 1, wherein said latch bracket has an inclined surface position for contact with said contact means.

3. The hook gate apparatus according to claim I, further comprising a feed dog lowering lever disposed in said recess. 

1. A hook gate apparatus for flat bed sewing machines comprising: a large recess formed in a sewing machine bed; a hook gate body disposed in said recess at an inclined angle to the flat surface of said bed; a latch bracket pivotally mounted in said recess for engagement with said hook gate body; a sliding plate slideable on said bed over said recess and capable of covering and uncovering said recess; contact means fixed to said sliding plate for coming temporarily into contact with said latch bracket during the sliding movements of said sliding plate from a closed to an open position and from an open to a closed position to initiate disengagement and engagement, respectively, of said latch bracket with said hook gate body, said contact means comprising a first member disposed on said sliding plate and extending vertically downwardly into said recess for temporarily contacting said latch bracket and a second member disposed on said sliding plate and extending vertically downwardly into said recess for contacting a stop member on said bed to limit the opening stroke of said sliding plate; mounting means for said latch bracket at the bottom of said recess permitting said latch bracket to be swung within said recess from a closed to an open position; and spring means attached to said bed and latch bracket to bias said latch bracket in a closed and open position.
 2. The hook gate apparatus of claim 1, wherein said latch bracket has an inclined surface position for contact with said contact means.
 3. The hook gate apparatus according to claim 1, further comprising a feed dog lowering lever disposed in said recess. 